Add support for Kafka version 2.8.0

[YemoAde]

• Kafka Version 2.8.0 has first release of KIP 500 (Removes dependence on zookeeper)
• However, current release is for development only because zookeeper is still required for Access Control List in Kafka
• See Kafka latest release log

[sycured]

I think that using an environment variable, we can change the startup between:

• with kraft
• with zookeeper

and having a default startup mode.

Just an idea to have a container supporting both modes.

[wurstmeister]

Thanks for your PR, it's been superseded by https://github.com/wurstmeister/kafka-docker/commit/85ca0564640b189f86c4f5842ab6d5fe0d80658e now